| /* |
| * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.crypto.provider; |
| |
| import java.math.BigInteger; |
| import java.security.*; |
| import java.security.spec.*; |
| import javax.crypto.spec.DHParameterSpec; |
| import javax.crypto.spec.DHGenParameterSpec; |
| |
| /* |
| * This class generates parameters for the Diffie-Hellman algorithm. |
| * The parameters are a prime, a base, and optionally the length in bits of |
| * the private value. |
| * |
| * <p>The Diffie-Hellman parameter generation accepts the size in bits of the |
| * prime modulus and the size in bits of the random exponent as input. |
| * The size of the prime modulus defaults to 2048 bits. |
| * |
| * @author Jan Luehe |
| * |
| * |
| * @see java.security.AlgorithmParameters |
| * @see java.security.spec.AlgorithmParameterSpec |
| * @see DHParameters |
| */ |
| public final class DHParameterGenerator extends AlgorithmParameterGeneratorSpi { |
| |
| // The size in bits of the prime modulus |
| private int primeSize = 2048; |
| |
| // The size in bits of the random exponent (private value) |
| private int exponentSize = 0; |
| |
| // The source of randomness |
| private SecureRandom random = null; |
| |
| private static void checkKeySize(int keysize) |
| throws InvalidParameterException { |
| |
| boolean supported = ((keysize == 2048) || (keysize == 3072) || |
| ((keysize >= 512) && (keysize <= 1024) && ((keysize & 0x3F) == 0))); |
| |
| if (!supported) { |
| throw new InvalidParameterException( |
| "DH key size must be multiple of 64 and range " + |
| "from 512 to 1024 (inclusive), or 2048, 3072. " + |
| "The specific key size " + keysize + " is not supported"); |
| } |
| } |
| |
| /** |
| * Initializes this parameter generator for a certain keysize |
| * and source of randomness. |
| * The keysize is specified as the size in bits of the prime modulus. |
| * |
| * @param keysize the keysize (size of prime modulus) in bits |
| * @param random the source of randomness |
| */ |
| @Override |
| protected void engineInit(int keysize, SecureRandom random) { |
| checkKeySize(keysize); |
| this.primeSize = keysize; |
| this.random = random; |
| } |
| |
| /** |
| * Initializes this parameter generator with a set of parameter |
| * generation values, which specify the size of the prime modulus and |
| * the size of the random exponent, both in bits. |
| * |
| * @param genParamSpec the set of parameter generation values |
| * @param random the source of randomness |
| * |
| * @exception InvalidAlgorithmParameterException if the given parameter |
| * generation values are inappropriate for this parameter generator |
| */ |
| @Override |
| protected void engineInit(AlgorithmParameterSpec genParamSpec, |
| SecureRandom random) throws InvalidAlgorithmParameterException { |
| |
| if (!(genParamSpec instanceof DHGenParameterSpec)) { |
| throw new InvalidAlgorithmParameterException |
| ("Inappropriate parameter type"); |
| } |
| |
| DHGenParameterSpec dhParamSpec = (DHGenParameterSpec)genParamSpec; |
| primeSize = dhParamSpec.getPrimeSize(); |
| exponentSize = dhParamSpec.getExponentSize(); |
| if ((exponentSize <= 0) || (exponentSize >= primeSize)) { |
| throw new InvalidAlgorithmParameterException( |
| "Exponent size (" + exponentSize + |
| ") must be positive and less than modulus size (" + |
| primeSize + ")"); |
| } |
| try { |
| checkKeySize(primeSize); |
| } catch (InvalidParameterException ipe) { |
| throw new InvalidAlgorithmParameterException(ipe.getMessage()); |
| } |
| |
| this.random = random; |
| } |
| |
| /** |
| * Generates the parameters. |
| * |
| * @return the new AlgorithmParameters object |
| */ |
| @Override |
| protected AlgorithmParameters engineGenerateParameters() { |
| |
| if (random == null) { |
| random = SunJCE.getRandom(); |
| } |
| |
| BigInteger paramP = null; |
| BigInteger paramG = null; |
| try { |
| AlgorithmParameterGenerator dsaParamGen = |
| AlgorithmParameterGenerator.getInstance("DSA"); |
| dsaParamGen.init(primeSize, random); |
| AlgorithmParameters dsaParams = dsaParamGen.generateParameters(); |
| DSAParameterSpec dsaParamSpec = |
| dsaParams.getParameterSpec(DSAParameterSpec.class); |
| |
| DHParameterSpec dhParamSpec; |
| if (this.exponentSize > 0) { |
| dhParamSpec = new DHParameterSpec(dsaParamSpec.getP(), |
| dsaParamSpec.getG(), |
| this.exponentSize); |
| } else { |
| dhParamSpec = new DHParameterSpec(dsaParamSpec.getP(), |
| dsaParamSpec.getG()); |
| } |
| AlgorithmParameters algParams = |
| AlgorithmParameters.getInstance("DH", SunJCE.getInstance()); |
| algParams.init(dhParamSpec); |
| |
| return algParams; |
| } catch (Exception ex) { |
| throw new ProviderException("Unexpected exception", ex); |
| } |
| } |
| } |